Cold start problems

[ChrisGoulding]

I have just had a look for the J52 relay and there doesn't appear to be one. There are ones which say 370, 167, 387, 202 and a few that say 373. There is one that says 53 on it. Could that be the right one? They all seem to click when the engine is turned on.
I also disconnected the G62 sensor and found that the glow plug light stayed on for around 15 seconds and then went out, but there was still power going to each glow plug continually. I can only conclude that the sensor is therefore working as as soon as I reconnected it, the power stopped going to the glow plugs.

[S3Quattro]

Its possible, you need to check the 12v supply at the relay. The terminals to test are labelled 85 and 86 on the glow plug relay. You will need to test the output to the glow plugs on terminal 87 at the same time to prove your theory.

[ChrisGoulding]

Cheers. I will have a look at that and will let you know.

[ChrisGoulding]

Finally, I have checked the relay and it is working correctly. I am beginning to think that this issue is nothing to do with the glow plugs, etc. What else can it be? The compression of the cylinders if normal so I am at at loss as to what it might be. Someone suggested that it may simply be the starter motor and battery connections need cleaning as they may stop the starter getting fully power when it really needs it. Whatever it is, its really starting to chuff me off!!!!! [img]/ubbthreads/images/graemlins/FIREdevil.gif[/img]

[njc021073]

Have you looked at the injectors.

They can cause big cold start problems (as any Volvo D5 owner will tell you).

Just a thought!

[ChrisGoulding]

I am no expert on these things, but if the injectors are blocked or faulty, would that not affect the performance of the engine at all times or even at EVERY start up? Or can they block up when left for a period of time which is cleared when started?

[njc021073]

I am also no expert (unfortunately), but do a google on Volvo D5 cold start problems, and you will see a lot of posts saying that cold starting problems were cured by replacing the injectors (at vast cost to customers).

My D5 is currently very sluggish starting when below 0 degrees (starter turns for at least 10 seconds before firing up) but there is no problem with the glow plugs and no smoke out the back when it does start. Start is fine when above 0 degrees.

Sorry about the Volvo thread creep.

[Crafty1980]

I've have exactly this problem with my 2002 A6 2.5TDi Quattro... It's especially bad when I take it to the Alps in the winter and, after a week of being parked up, it just doesn't start... I had to resort to starting it and driving it up and down the mountain every day for 40mins or so (or until it was warm) and then parking it again. I did find a whole section in the manual about starting problems in the extreme cold so they (Audi) clearly know there's a problem with this car when it comes to starting in the cold!

The garage can't find anything wrong with it either. I've had glow plugs, battery, various temp sensors, all changed... Engine flushed too... Still did nothing to help. I've had to resort to taking a jump start with me to make sure the car fires so I could get home!

Incidentally, the car is absolutely rubbish at altitude too... I absolutely love it to bits but it doesn't half annoy me for a couple of weeks every year when I head off to the Alps! It loses nearly all power over 1250m... Feels like driving in "get me home" mode.

[PetrolDave]

UK cars are not equipped with the same injectors and pre-heaters as cars sold into cold climates - so when we visit cold climates we get cold starting problems that locally sold cars don't experience.

Fitting new UK-spec parts (which is what a UK dealer will do) won't help - the parts need to be replaced with the versions fitted to cold climate spec cars.

[Ady_E]

Originally Posted by ChrisGoulding

Other threads suggest fuel pumps, etc but I would be surprised if it was something serious like that as it runs smoothly once it has been started.

Turn the power on without starting the engine, If you here a buzzing noise for a second or so, that's the fuel pump pressurising the fuel rail, so it's, at least, electrically sound. I'm sure this side of things work the same way for diesels as it does for petrol engines. (If I'm wrong, I'm sure someone will correct me. )

Originally Posted by ChrisGoulding

I have just had the error codes scanned and it has come back with an intermitant fault with the G62 coolant sensor.

Because this is an 'intermitant' fault, it could just mean the garage (or someone else) may have unplugged it at some point in an effort to diagnose the ploblem. Fault finding by process of elimination if you like. Clear that code and see if it re-apears.